Develop Reference

SQLite database does not exist according to Java application

I have looked at every possible answer on this site, nothing quite covers the issue.
I followed a tutorial and tried using the Firefox SQLite Manager AND using the SQLite3 shell to create the same database.
public class DBConnector {
static Connection conn = null;
public static Connection connect()
{
try{
Class.forName("org.sqlite.JDBC");
conn = DriverManager.getConnection("jdbc:sqlite:‪C:\\Users\\John\\Desktop\\database.db");
return conn;
}
catch(Exception e){
e.printStackTrace(System.out);
return null;
}
}
}
Whenever I run this i get:
java.sql.SQLException: path to '‪C:\Users\John\Desktop\database.db': 'C:\Users\John\Documents\NetBeansProjects\JBook\‪C:' does not exist
I'm new enough to this to where I have no idea what the issue is.
Any help is greatly appreciated. And yes, I have looked at all of the other questions posted and tried using their answers, to no avail.
Thanks again
EDIT: A couple of the possible answers already listed have included to change the .db extension to .sqlite
This did NOT work.
Another simply showed how to use an absolute path, once again, I had that covered and it didn't work.
Another talked about JUnit test and some issue they were having which was irrelevant to what I am doing

Finally got the issue:
Copy the path you specified in notepad++ and set encoding to ansi and you will see some special character before C: which is causing issue .
conn = DriverManager.getConnection("jdbc:sqlite:‪C:\\Users\\ravi\\Desktop\\database.db");
conn = DriverManager.getConnection("jdbc:sqlite:C:\\Users\\ravi\\Desktop\\database.db");

AWS Lambda Java, connect to MySQL RDS

I need to develop an AWS Lambda Java function to retrieve some records from RDS MySQL database.
Should I use JDBC? Should I use the standard JDBC example:
try {
String url = "jdbc:msql://200.210.220.1:1114/Demo";
Connection conn = DriverManager.getConnection(url,"","");
Statement stmt = conn.createStatement();
ResultSet rs;
rs = stmt.executeQuery("SELECT Lname FROM Customers WHERE Snum = 2001");
while ( rs.next() ) {
String lastName = rs.getString("Lname");
System.out.println(lastName);
}
conn.close();
} catch (Exception e) {
System.err.println("Got an exception! ");
System.err.println(e.getMessage());
}

Step 1:
login IAM console
roles -> create new roles
role name :lambda-vpc-execution-role
AWS service roles ->
a) Select aws lambda
b) Attach policy "AWSLambdaFullAccess"
Step 2:
Get code from https://github.com/vinayselvaraj/lambda-jdbc-sample (note this is maven project)
Right click on project select Run as --->5.maven build...
for goal provide name package shade:shade
Go to project folder and target/lamda-0.0.1-SNAPSHOT-shaded.jar
Step 3:
Login to lambda console(skip blueprint)
Create new lambda
name: time-test
a) runtime-java
b) upload .zip(.jar) file (target/lamda-0.0.1-SNAPSHOT-shaded.jar)
Provide package.class-name::myhandler -> Handler
Role -> lambda-vpc-exceution-role
vpc provide rds-vpc details (this should work in same vpc group)
Create function
In the Action drop down list select configure test event
result will shown down like this "Execution result: succeeded (logs)"

Yes, you need to use standard JDBC code in your lambda function class. The code you provided looks okay. There are a few more things you need to do when accessing RDS or any other RDBMS through a Lamda function -
Create a jar or a zip file for your Lambda function
Your zip file needs to have a lib folder in which your JDBC driver file goes. The Lambda function doc says this is one of the two standard ways, but it didn't work for me.
You can create a jar file in which the driver classes are put in. This works. The best way to do it is through the Maven Shade plugin, which extracts the JDBC drivers and packs the classes in one single jar file.
Setup the handler function and specify it at the time of Lambda deployment
Define execution role and VPC as needed.
Upload and publish your jar or zip file.
You can test the Lambda function through the console, and see the actual output in the CloudWatch logs.

You could use this kinda implementation:
public static DataSource getDataSource(){
Utils._logger.log("Get data source");
MysqlDataSource mysqlDs = null;
try{
mysqlDs = new MysqlDataSource();
mysqlDs.setURL('jdbc:msql://'+'url');
mysqlDs.setUser('user');
mysqlDs.setPassword('pwd');
Utils._logger.log("Object "+mysqlDs.getUrl()+" "+mysqlDs.getUser()+" ");
return mysqlDs;
}
catch(Exception e) {
Utils._logger.log("No se pudo abrir el archivo de properties");
e.printStackTrace();
}
return mysqlDs;
}

One thing I am particularly noticing in your codebase is that even when you use this Lambda function for connecting to the specific RDS you have, the hostname may not be the correct one for Amazon RDS.
It needs to be the endpoint of the RDS you are trying to connect to and your complete connection url would look something like this below -
//jdbc:mysql://hostname (endpoint of RDS):port/databasename
String url = "jdbc:mysql://"+dbHost+":3306/"+dbName;
Since those endpoints can change for different databases and servers, you can make them as environment variables within Lambda and refer using
String dbHost = System.getenv("dbHost");
String dbName = System.getenv("dbName");
for a much cleaner and stateless design that Lambda supports.

Java JDBC Sybase JConnect

I need to connect to my SQL Anywhere 11 (Sybase) database using the JConnect(jConn3.jar) driver from sybase from my Java application. I have tried the documentation and contacted the technical support, but valid help has been naught :(. Also if anyone maybe knows how to connect to Crystal Reports XI using this driver, help would be greatly appreciated...

Make sure your jconn3.jar is on the classpath of your application. Then use your jdbc driver as following:
try {
Class.forName("com.mysql.jdbc.Driver").newInstance();
String url = "jdbc:mysql://localhost/coffeebreak";
conn = DriverManager.getConnection(url, "username", "password");
// Do your stuff
conn.close();
} catch (Exception ex) {
...
}
Your comment on my answer helped. We encountered this kind of problem too. Our project used the viewer in a JSP. The problem occured while drilling down our report.
When you open your report the first time, the viewer generates an identifier for your report. You have to store that in the session so when you drill down, you can use this identifier. This way, you indicate that it is still the same report and the viewer will use the same datasource.
Here is a piece of code, which should be clearer than text:
// Report viewer
CrystalReportViewer crystalViewer = new CrystalReportViewer();
// Key to store the report source
String reportSourceSessionKey = "anyKeyYouWant";
Object reportSource = null;
// Get the report name passed in parameter
String reportName = request.getParameter("report");
if (reportName != null) {
// Build your report
ReportClientDocument reportClientDoc = new ReportClientDocument();
// ...
// Store de report source
reportSource = reportClientDoc.getReportSource();
session.setAttribute(reportSourceSessionKey, reportSource);
// Close the report document
reportClientDoc.close();
} else {
reportSource = session.getAttribute(reportSourceSessionKey);
}
// Set the source of the viewer
crystalViewer.setReportSource(reportSource);
....
This solved our JNDI problem. Hope it does it for you.

Use Database in java application

I am beginner in Java application programming.
I've created a database application in Java. I use an MS access database with the JDBC-ODBC driver. My application's create-connection code is below:
private void connection() {
try {
String driverurl = "jdbc:odbc:dharti_data";
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
con = DriverManager.getConnection(driverurl,"","");
} catch (SQLException e) {
JOptionPane.showMessageDialog(frm,e.getSQLState(),"Database Access Error",JOptionPane.ERROR_MESSAGE);
} catch (Exception e) {
JOptionPane.showMessageDialog(null,e.getMessage(),"Database Access Error",JOptionPane.ERROR_MESSAGE);
}
}
This code works perfectly, but this code uses a datasource name I declared in Control Panel > Administrative Tools > Data Sources (ODBC) > System DSN > Add Data Source, with a Microsoft Access Driver (*.mdb).
But when I run the application on another PC, it can't run and instead it generates a database error.
I know that I can declare a driver in Data Sources (ODBC) > System DSN, and then it will run. But I don't want to do this on every machine I run my application on. My application should be able to pick up the database connection automatically. How can I make my application not require a data-source name?

String filename = "C:/Lab/northwind.mdb"; // this the path to mdb file
String database = "jdbc:odbc:Driver={Microsoft Access Driver (*.mdb)};DBQ=";
database+= filename.trim() + ";DriverID=22;READONLY=true}"; // add on to the end
// now we can get the connection from the DriverManager
Connection con = DriverManager.getConnection( database ,"","");

Im not sure if I got this, but are you shipping the jdbc driver along with your application? It has to be in your classpath and needs to be deployed with your application.

You will have to programmatically modify these registry sections:
HKEY_LOCAL_MACHINE\SOFTWARE\ODBC\ODBC.INI and
HKEY_LOCAL_MACHINE\SOFTWARE\ODBC\ODBC.INI\ODBC
Ice Engineering offer a public domain api that allows you to do that. Beside jars it has a DLL that you have to ship with your application. It is fairly straight forward and will work.
In order to get a better idea of what you have to do, use regedit in order to see the values before installing anything, then install an ODBC database manually, finally compare the new values with the old.

I used the sun.jdbc.odbc.JdbcOdbcDriver to connect to a MS Access database. Have that in the same directory as the class file and it should work. Although it should come already installed in the Java SDK.
This is a sample of a practice program I made a while ago.
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
System.out.println("Driver loaded");
// Establish a connection
Connection connection = DriverManager.getConnection
("jdbc:odbc:Driver={Microsoft Access Driver (*.mdb)};DBQ=(MS ACCESS DATABASE DIRECTORY)");
System.out.println("Database connected");
// Create a statement
Statement statement = connection.createStatement();
// Execute a statement
ResultSet resultSet = statement.executeQuery
("select f_name, l_name from Test where f_name = 'Luke'"); // For example
// Iterate through the result and print the results
while (resultSet.next())
System.out.println(resultSet.getString(1) + "\t" + resultSet.getString(2) );

integrate ms access and mysql in java

I have a problem connecting to MS Access and MySQL using Java. My problem is that I cannot find the driver for MySQL. Here is my code:
<%# page import="java.sql.*" %>
<%
Connection odbcconn = null;
Connection jdbcconn = null;
PreparedStatement readsms = null;
PreparedStatement updsms = null;
ResultSet rsread = null;
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); //load database driver
odbcconn = DriverManager.getConnection("jdbc:odbc:SMS"); //connect to database
readsms = odbcconn.prepareStatement("select * from inbox where Status='New'");
rsread = readsms.executeQuery();
while(rsread.next()){
Class.forName("com.mysql.jdbc.Driver");
jdbcconn = DriverManager.getConnection("jdbc:mysql://localhost:3306/bakme", "root", ""); //connect to database
updsms = jdbcconn.prepareStatement("insert into inbox(sms,phone) values (?,?)");
updsms.setString(1, rsread.getString("Message"));
updsms.setString(2, rsread.getString("Phone"));
updsms.executeUpdate();
}
%>

Thus, you get a ClassNotFoundException on the MySQL JDBC driver class? Then you need to put the MySQL JDBC driver JAR file containing that class in the classpath. In case of a JSP/Servlet application, the classpath covers under each the webapplication's /WEB-INF/lib folder. Just drop the JAR file in there. Its JDBC driver is also known as Connector/J. You can download it here.
That said, that's really not the way how to use JDBC and JSP together. This doesn't belong in a JSP file. You should be doing this in a real Java class. The JDBC code should also be more robust written, now it's leaking resources.

BalusC is spot on: this is not the way you should write something like this.
Connection, Statement, and ResultSet all represent finite resources. They are not like memory allocation; the garbage collector does not clean them up. You have to do that in your code, like this:
// Inside a method
Connection connection = null;
Statement statement = null;
ResultSet rs = null;
try
{
// interact with the database using connection, statement, and rs
}
finally
{
// clean up resources in a finally block using static methods,
// called in reverse order of creation, that don't throw exceptions
close(rs);
close(statement);
close(connection);
}
But if you do decide to move this to a server-side component, you're bound to have huge problems with code like this:
while(rsread.next())
{
Class.forName("com.mysql.jdbc.Driver");
jdbcconn = DriverManager.getConnection("jdbc:mysql://localhost:3306/bakme", "root", ""); //connect to database
updsms = jdbcconn.prepareStatement("insert into inbox(sms,phone) values (?,?)");
updsms.setString(1, rsread.getString("Message"));
updsms.setString(2, rsread.getString("Phone"));
updsms.executeUpdate();
}
Registering the driver, creating a connection, without closing it, and repeatedly preparing a statement inside a loop for every row that you get out of Access shows a serious misunderstanding of relational databases and JDBC.
You should register the driver and create connections once, do what needs to be done, and clean up all the resources you've used.
If you absolutely MUST do this in a JSP, I'd recommend using JNDI data sources for both databases so you don't have to set up connections inside the page. You should not be writing scriptlet code - better to learn JSTL and use its <sql> tags.

You can use this link to download the MySql Driver. Once you download it, you need to make sure it is on the class path for the web server that you are using. The particulars of configuring JDBC drivers for a server vary from server to server. You may want to edit your question to include more details to get a better answer.